This invention relates to a method of making an electrical connection of a fine wire or single filament to a cylindrical connector and, more particularly, the invention is concerned with providing a method of attaching a high temperature filament to a cylindrical connector by inserting a coiled wire into the connector to reduce the initial diameter, slipping the filament into the center of the coiled wire and lightly crimping the cylindrical connector.
Heretofore, it has been common practice to attach fine diameter wires and filaments by spot welding the filament to the filament holder or, in the alternative, to provide specially designed filament holders. These previous techniques generally result in damage to the fine diameter wires and filaments and cause highly stressed areas which produce stress concentrations at the joint. This condition usually results in early joint failure. Other attachment techniques such as clamping, brazing, twisting or wrapping, also cause the filament to be highly stressed and reduced in cross section producing early joint failure. Since the cylindrical end of nearly all commercially available connectors is much too large a diameter for the fine wire or filament to be attached with light pressure, some other means of attachment is required.
It would be most desirable to reduce the diameter of the tubular portion of the cylindrical connector by filling the portion of the volume with an element which will operate to hold the filament firmly in place and electrically joined without weakening the filament. This requires that the filament be gripped over a relatively long length and that a tight fit be obtained with a very light crimping of the outer cylinder, thereby avoiding high stress concentrations making the joint as strong as the wire filaments.